WO2019112011A1

WO2019112011A1 - Foam

Info

Publication number: WO2019112011A1
Application number: PCT/JP2018/044936
Authority: WO
Inventors: 基久清水; 幸周和田; 萩原　昌彦
Original assignee: 宇部興産株式会社
Priority date: 2017-12-06
Filing date: 2018-12-06
Publication date: 2019-06-13
Also published as: JP7327164B2; JPWO2019112011A1

Abstract

This foam contains a cellulose fiber and polypropylene. The content of the cellulose fiber falls within a range of 10 to 65 mass%, and the density is 80 kg/m3 or less.

Description

Foam

The present invention relates to a foam comprising cellulose fibers and polypropylene.
Priority is claimed on Japanese Patent Application Nos. 2017-234423, 2017-234424 and 2017-234425, filed Dec. 6, 2017, the contents of which are incorporated herein by reference. I will use it.

Foams are used in various applications such as heat insulating materials, shock absorbing materials, packaging materials, etc. because they are excellent in shock absorbing properties against physical impact and heat insulating properties. In recent years, a composition containing cellulose fiber and polypropylene has attracted attention as a foam material.
For example, Patent Document 1 describes a foam obtained by supplying a paper component, a thermoplastic resin, and water to an extruder, heating and kneading the mixture in the extruder, and foaming at a water vapor pressure. Further, in Patent Document 1, the density is manufactured by using a powdery polypropylene homopolymer as a thermoplastic resin, using a crushed material having a side length of about 3 mm to 5 mm obtained by crushing waste paper with a crusher as a paper component A foam of 0.085 g / cm ³ (85 kg / m ³ ) is described.

JP 2000-273800 A

However, foams containing conventional cellulose fibers do not have sufficient heat insulation when used as a heat insulating material, and it has been required to improve the heat insulation.
The present invention has been made in view of the above-mentioned circumstances, and an object of the present invention is to provide a foam which contains cellulose fibers and can provide sufficient heat insulation when used as a heat insulating material.

The present invention adopts the following configuration in order to solve the above-mentioned problems.
[1] A foam comprising cellulose fiber and polypropylene, wherein the content of the cellulose fiber is in the range of 10% by mass to 65% by mass, and the density is 80 kg / m ³ or less.
[2] The foam according to the above [1], which is in the form of strands or in the form of strands in which a plurality of particulate foam particles are connected in a string form.

[3] The foam according to the above [1], which comprises the cellulose fiber and the polypropylene and has a density of 70 kg / m ³ or less.

[4] Furthermore, the resin additive contains a resin additive, and the resin additive is vinyl resin, polystyrene resin, polyester resin, polyamide resin, acrylic resin, polyether resin, polyimide resin, elastomer resin, At least one selected from the group consisting of sulfur-containing resins, phenolic resins and epoxy resins, and the content of the resin additive is in the range of 0.1% by mass to 30% by mass, and the polypropylene The foam as described in said [1] whose content of 5 mass% or more.
[5] The foam according to [4], which has a density of 70 kg / m ³ or less.

[6] Furthermore, the above-mentioned content of polyurethane is within the range of 1 mass% or more and less than 20 mass%, and the content of the above-mentioned polypropylene is within the range of 15 mass% or more and 89 mass% or less The foam as described in [1].

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the foam which contains a cellulose fiber and can obtain sufficient heat insulation when it is used as a heat insulating material.

Hereinafter, an embodiment of the foam of the present invention will be described.
The foam of this embodiment contains cellulose fiber and polypropylene. The content of cellulose fiber is in the range of 10% by mass to 65% by mass.

(Cellulose fiber)
As a material of the cellulose fiber contained in the foam of the present embodiment, 1 type or 2 selected from woody fibers such as softwoods and hardwoods, non-woody fibers, gin skin fibers, fibers derived from bacteria, etc. More than species can be used. Specifically, for example, mechanical pulp (MP; mechanical pulp, GP; ground pulp, RGP; refiner ground pulp, TMP; thermomechanical pulp, CTMP; chemithermomechanical pulp, etc.), chemical pulp (KP; Kraft, etc.) Pulp, SP: sulfided pulp, AP: alkaline pulp, etc., recycled pulp (recycled paper such as used paper and scraps, corrugated cardboard), etc. can be used.

Examples of conifers used as the material of cellulose fiber include pines, black pines, Japanese spruce, larch, larch, radiata pine, long leaf pine, short leaf pine, slush pine, loblolly pine, white spruce, black spruce, fir, Douglas Fur, balsam fur, cedar, cypress and the like. Examples of hardwood include beech, nara, oak, eucalyptus, poplar and the like. Examples of non-woody fibers include linters, cotton, rice straw, straw, oil palm empty bunches (EFB), bamboo, sugar cane bagasse, hemp, cannabis, manila hemp, flax, persimmon and the like. Examples of ginseng fibers include silkworm, Mitaka and the like. Examples of fibers derived from bacteria include bacterial cellulose and the like.

As the cellulose fibers contained in the foam of this embodiment, it is preferable to use one obtained by disintegrating and / or crushing paper, and it is preferable to use one obtained by disintegrating waste paper. It does not specifically limit as a method to disintegrate paper, For example, a stone type grinder, a refining machine, a shredder, a cone crusher, a roll crusher, a cutter mill, an autogenous pulverizer, a stamp mill, a mortar, a mortar machine A grinder such as a roller mill, a ring mill, a jet mill, a hammer mill, a pin mill, a rotary mill, a vibration mill, a planetary mill, a bead mill, and an attritor can be used. As a crusher, for example, a stone mill type crusher manufactured by Masuko Sangyo Co., Ltd. (trade name: Muscoloyder), a beating machine manufactured by Aikawa Tekko KK (trade name: RF single refiner), a hand shredder manufactured by Sanwa Supply Co., Ltd. Trade name: PSD-12) and the like.

As a cellulose fiber used as a foam material, it is preferable to use one having an average particle diameter of 10 μm to 5 mm measured by a measurement method described later, and more preferably to use 20 μm to 3 mm. When the average particle size of the cellulose fiber is 10 μm or more, the energy required for the crushing may be small, so the load on the environment may be small and the manufacturing cost may be small, which is preferable. When the average particle diameter of the cellulose fiber is 5 mm or less, high magnification foaming can be performed and a low density foam can be obtained, which is preferable.

"Method of measuring average particle size of cellulose fiber"
The average particle diameter of the cellulose fiber used as a material of a foam in this embodiment means that it is the value measured using the method 1 or the method 2 shown below. In the present embodiment, method 1 or method 2 is used according to the average particle size of the cellulose fiber. If the average particle size of the measured cellulose fibers is within the range of both method 1 and method 2, one or more of the two methods may be used.

(Method 1: Cellulose fiber having a particle size in the range of 0.01 μm to 3000 μm)
A dispersion is prepared by dispersing cellulose fibers of a sample in ion-exchanged water as a dispersion medium. Next, the dispersion is irradiated with ultrasonic waves for 30 minutes in an ultrasonic bath as a pretreatment. Thereafter, with respect to the sample in the dispersion liquid, the particle size measurement is performed under the measurement conditions shown below using a measuring device shown below.
The particle size measurement is carried out after the dispersion is placed in the cell of the measuring device and irradiated with ultrasonic waves for 1 minute in the measuring device. In addition, the dispersion medium alone is put in advance in the cell of the measuring device, and the particle size is measured as a blank.
The measurement is carried out twice for each dispersion to calculate an average value, which is taken as the average particle size of the sample.

Measuring device: Laser diffraction / scattering type particle size distribution measuring device (manufactured by HORIBA, Ltd., trade name: LA-950V2)
Measurement conditions: Measurement unit: Wet Measurement mode: Manual flow cell measurement Particle diameter standard: Volume standard Refractive index: 1.50-0.00i (sample refractive index) /1.33-0.00i (dispersion medium refractive index)

(Method 2: Cellulose fiber containing long fibers having a particle size of 3000 μm or more)
Cellulose fibers of a sample are uniformly dispersed on a paper surface of 60 mm long and 80 mm wide, and images of any three places are taken. Subsequently, the length of 100 or more cellulose fibers is measured for each image using a digital camera system for microscope (GOKO Inter, Inc., Macromax) and measurement software (GOKO Inter, Inc., GOKO Measure), respectively. The length of cellulose fibers is measured along the shape of the fibers. However, in the case of a shape in which cellulose fibers are aggregated, the longest part is measured. The particle size distribution (histogram) is determined with the length of the cellulose fiber thus measured as the equivalent circle diameter, and the volume average diameter (MV) is calculated. The volume average diameter (MV) is calculated using the attached software (HORIBA NEXTGEN Project LA-950 for Windows Ver 7.02), a trade name of LA-950 V2 manufactured by HORIBA, Ltd. The volume average diameter (MV) is expressed by the following equation.
MV = Σ (vd) / Σv
(D in the equation represents a section representative value of the particle size distribution histogram, and v represents the frequency of the volume (the volume of the sphere when the fiber length is the equivalent circle diameter) with respect to the whole particle included in each section. The representative value indicates the square root of the product of the section lower limit value and the section upper limit value.)

The foam of the present embodiment has a cellulose fiber content in the range of 10% by mass to 65% by mass. When the content of the cellulose fiber is 10% by mass or more, a foam having a low density is easily obtained. Moreover, content of a polypropylene can fully be ensured as content of a cellulose fiber is 65 mass% or less, and strength of a foam does not run short.
In addition, content of the cellulose fiber and polypropylene in a foam can be regarded as the same as the ratio of content of the cellulose fiber and polypropylene which were used as a material of a foam.

(polypropylene)
As polypropylene used as a material of foam, for example, those having MFR (melt flow rate, temperature: 230 ° C., load: 2.16 kg) in the range of 0.1 g / 10 minutes to 100 g / 10 minutes It is preferred to use. Polypropylene may be used individually by 1 type, and may use together 2 or more types of polypropylene from which characteristics, such as MRF, differ. For example, low MFR polypropylene having an MFR (temperature: 230 ° C., load: 2.16 kg) in the range of 0.1 g / 10 minutes to 20 g / 10 minutes and MFR (temperature: 230) more than the low MFR polypropylene Two kinds of high MFR polypropylene having a high temperature of 2.16 kg) may be used in combination. By using two or more types of polypropylene having different properties in combination, the density and thermal conductivity of the foam can be adjusted to be in the desired range.

The shape of the polypropylene used as the material is preferably in the form of pellets or powder. The pellet-like polypropylene has, for example, a fixed shape such as a spherical shape, a hemispherical shape, an almond shape, a cylindrical shape, a prismatic shape, a plate shape, and a flake shape. Powdered polypropylene is obtained by pulverizing the above-mentioned pelletized polypropylene into powder. The powdery polypropylene preferably has a particle size of 2 mm or less.

The foam of the present embodiment is preferably in the form of a plurality of granular foam particles connected in a string or in the form of a strand. The granular foam particles constituting the beaded foam are preferably spherical. However, the granular foam particles do not have to be true spheres, and may be elliptic spheres or may have irregularities on the surface. The foam of this embodiment can be cut and processed into various sizes for use. For example, in the case of beaded foam, it may be divided into individual granular foam particles for use. In the case of a strand-like foam, it may be cut and used as granular granular foam particles, or a plurality of strand-like foams may be fused and integrated in a bundle. You may use it by

The foam of the present embodiment may be composed of a two-component composition of cellulose fiber and polypropylene, or may be composed of a composition containing other components other than cellulose fiber and polypropylene. Examples of other components include flame retardants, fiber-based reinforcements, and foam assistants. Hereinafter, the composition of the foam of the present embodiment will be described.

First Embodiment
The foam of the first embodiment comprises the above-mentioned cellulose fiber and the above-mentioned polypropylene. That is, in the foam of the first embodiment, the content of cellulose fibers is in the range of 10% by mass to 65% by mass, and the balance is polypropylene. It is preferable that content of a cellulose fiber exists in the range of 15 mass% or more and 60 mass% or less.

The foam according to the first embodiment is a foam having a density of 70 kg / m ³ or less, which is composed of 10% by mass to 65% by mass of cellulose fibers and 35% by mass to 90% by mass of polypropylene. It has been completed based on the finding that sufficient thermal insulation can be obtained when it is used as

The foam of the first embodiment has a density of 70 kg / m ³ or less and preferably 66 kg / m ³ or less. When the density of the foam exceeds 70 kg / m ³ , sufficient insulation may not be obtained when used as a heat insulating material. On the other hand, if the density of the foam is too low, the strength of the foam may be insufficient and the application may be limited. Therefore, the density of the foam is preferably 10 kg / m ³ or more, and more preferably 15 kg / m ³ or more.

Next, a method of manufacturing the foam of the first embodiment will be described.
The method for producing a foam according to the first embodiment is a step of kneading cellulose fibers and polypropylene to form a first kneaded product containing cellulose fibers in the range of 10% by mass to 65% by mass (first example) Process for producing a second kneaded product (kneaded product forming process), and a process for producing a second kneaded product by kneading the first kneaded product and water (a second kneaded product forming process), and evaporating the water of the second kneaded product to form a foam. And a step of generating (foam generation step).

A continuous kneader and a batch kneader can be used as a kneader for kneading cellulose fibers and polypropylene in the first kneaded product forming step. Examples of continuous kneaders include single-screw kneaders and twin-screw kneaders. Examples of the batch type kneader include a Banbury mixer and a pressure type kneader.

Since the density of the cellulose fiber and the polypropylene to be kneaded in the first kneaded product forming step are largely different, it is preferable to previously mix the cellulose fiber and the polypropylene into a mixture before feeding into the kneading apparatus. By supplying the mixture of the cellulose fiber and the polypropylene to the kneading apparatus, the first kneaded material having a uniform composition in a short time can be obtained.

It is preferable to use a continuous-type kneader as a kneading apparatus which knead | mixes a 1st kneaded material and water in a 2nd kneaded material production | generation process. Examples of continuous kneaders include single-screw kneaders and twin-screw kneaders. The continuous kneader preferably has a water introducing means for introducing water in the middle of the cylinder part.

Kneading conditions such as temperature of cylinder part of continuous kneader, temperature of die part, screw rotation speed, feed rate of water to continuous kneader, etc. are content of cellulose fiber and polypropylene, material and shape, purpose It can be suitably determined according to the density range of the foam and the like.

The first kneaded product forming step and the second kneaded product forming step may be performed continuously. For example, using a continuous kneader as a kneader, polypropylene and cellulose fibers are charged into the continuous kneader to form a first kneaded product, and then water is supplied to the continuous kneader to perform first kneading The substance and water may be kneaded to form a second kneaded product. As described above, by continuously performing the first kneaded material forming step and the second kneaded material forming step, the second kneaded material having a uniform composition can be obtained in a relatively short time.

In the foam generation step, the moisture of the second kneaded material extruded from the die portion of the continuous kneader is evaporated to generate a foam. The evaporation of the water content of the second kneaded material can be performed under the atmosphere. Usually, the water content of the second kneaded material is evaporated while being extruded from the die portion of the continuous kneader, and the foam of the first embodiment is generated. The generated foam may be cut into lengths according to the use application, if necessary.

The foam of the first embodiment described above is a foam having a density of 70 kg / m ³ or less, which is composed of 10% by mass to 65% by mass of cellulose fibers and 35% by mass or more of polypropylene. For this reason, the heat conductivity is low, and when used as a heat insulating material, sufficient heat insulation can be obtained.
Moreover, according to the foam manufacturing method of the present embodiment, the second kneaded material obtained by kneading the first kneaded material containing the cellulose fiber in the range of 10% by mass to 65% by mass and water. By evaporating the water to form a foam, a foam with a large amount of foam is obtained.

Second Embodiment
The foam of the second embodiment comprises the cellulose fiber, the polypropylene and the resin additive.

The foam of the second embodiment has a low density by using a foam containing cellulose fibers, polypropylene and a specific resin additive at a specific content, and the heat insulation is sufficient when used as a heat insulating material Were completed based on the finding that

Resin additives include vinyl resins, polystyrene resins, polyester resins, polyamide resins, acrylic resins, polyether resins, polyimide resins, elastomer resins, sulfur-containing resins, phenol resins and epoxy resins And at least one selected from the group consisting of

Examples of vinyl resins used as resin additives include polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polyvinyl alcohol (PVA), ethylene / vinyl acetate copolymer (EVA), and trifluorinated chlorinated ethylene (PCTFE). ), Tetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-perfluoroalkoxyethylene copolymer (PFA), tetrafluoroethylene-ethylene copolymer And coalesced (ETFE), vinylidene fluoride (PVDF), polyethylene (PE) and the like.
The vinyl-based resin is a resin having a polymerization unit represented by the formula (1), and preferably has a weight average molecular weight of 10,000 to 200,000,000. In addition, the arrangement order of the repeating units [CR ₁ (R ₂ ) -CR ₃ (R ₄ )] and [CR ₅ (R ₆ ) -CR ₇ (R ₈ )] in the formula (1) is particularly restricted. There is no. Therefore, Formula (1) may contain any of a random copolymer, a block copolymer, and an alternating copolymer.

In formula (1), R ₁ , R ₂ , R ₃ , R _4, R ₅ , R ₆ , R ₇ and R ₈ are each independently a hydrogen atom, a halogen atom, a hydroxyl group (-OH), an acetyloxy And any one group selected from a group (-OCOCH ₃ ), trifluoromethyl group (-CF ₃ ), trifluoromethoxy group (-OCF ₃ ), and linear or cyclic alkyl group having 1 to 10 carbon atoms . R ₁ , R ₂ , R ₃ , R ₄ , R ₅ , R ₆ , R ₇ and R ₈ may all be different groups, or some or all of them may be the same group. l is 40 to 100 mol%. m is 0 to 60 mol%.

Examples of polystyrene resins include polystyrene (PS), styrene / acrylonitrile copolymer (AS), styrene / butadiene / acrylonitrile copolymer (ABS) and the like.
The polystyrene resin is a resin having a polymerization unit represented by the formula (2), and preferably has a weight average molecular weight of 2,000 to 4,000,000. In addition, there is no restriction | limiting in particular in the arrangement | sequence order of the repeating unit in Formula (2). Therefore, Formula (2) may contain any of a random copolymer, a block copolymer, and an alternating copolymer.

Ph shows a phenyl group in Formula (2). x is 0 to 95 mol%. y is 0 to 95 mol%. z is 5 to 100 mol%.

Examples of polyester resins include polyethylene terephthalate (PET) and polybutylene terephthalate (PBT).
The polyester resin is preferably a resin represented by the formula (3), and preferably has a weight average molecular weight of 1,000 to 1,000,000.

In formula (3), p is 1 or 2. r is 2 to 10,000.

Examples of polyamide-based resins include nylon 6, nylon 6, 6 and nylon 12 and the like.
The polyamide resin is preferably a resin represented by the formula (4) or the formula (5), and the weight average molecular weight is preferably 500 to 5,000,000.

In the formula (4), q is 4 to 10. s is 2 to 30,000.

In the formula (5), g is 2 to 5. h is 2 to 10. t is 2 to 30,000.

Examples of acrylic resins include polymethyl methacrylate (PMMA), methyl methacrylate / styrene copolymer (MS) and the like.
The acrylic resin is a resin having a polymerization unit represented by the formula (6), and preferably has a weight average molecular weight of 1,000 to 3,000,000. In addition, there is no restriction | limiting in particular in the arrangement | sequence order of the repeating unit in Formula (6). Therefore, Formula (6) may contain any of a random copolymer, a block copolymer, and an alternating copolymer.

In the formula (6), R ₉ is any one group selected from a hydrogen atom and an alkyl group of 1 to 5 carbon atoms. Ph represents a phenyl group. i is 5 to 100 mol%. u is 0 to 95 mol%.

Examples of polyether resins include polyacetal (POM), polyphenylene ether (PPE), polyether ketone (PEK), polyether ether ketone (PEEK), polyether sulfone (PES) and the like.
The polyether resin is preferably a resin having a polymerization unit represented by Formula (7), and the weight average molecular weight is preferably 500 to 2,000,000.
In the polymerized unit represented by the formula (7), examples of the substituent include a carbonylphenyl group, a phenyl group and a sulfonylphenyl group.

In formula (7), A is —CH ₂ — or a phenylene group (—C ₆ H ₄ —) which may have one or more substituents.

The polyimide resin is preferably a resin represented by the formula (8), and the weight average molecular weight is preferably 1,000 to 9,000,000.

In the formula (8), Ar is a group represented by the following formula (9) or the following formula (10). R ₁₀ is any group represented by the following formulas (11) to (15). w is 1 to 30,000.

As an elastomer resin, polycarbonate (PC) etc. are mentioned, for example.
Examples of sulfur-containing resins include polysulfone (PSF) and polyphenylene sulfide (PPS).
As a phenol resin, novolak resin, resol resin, etc. are mentioned, for example.
As an epoxy resin, the copolymer of bisphenol A and epichlorohydrin etc. are mentioned, for example.

The resin additive contained in the foam of the present embodiment may be a polymer alloy or a polymer blend in which a plurality of the above resins are mixed.
Among the above-described resin additives, polyvinyl chloride (PVC), polyvinylidene chloride (PVDC), polyvinyl alcohol (PVA), ethylene / vinyl acetate copolymer (EVA), polyethylene (PE), polystyrene (PS) Or at least one selected from styrene / acrylonitrile copolymer (AS), styrene / butadiene / acrylonitrile copolymer (ABS), polymethyl methacrylate (PMMA), methyl methacrylate / styrene copolymer (MS) Is preferred.

In particular, it is preferable to use at least one selected from polystyrene (PS), styrene-acrylonitrile copolymer (AS), and styrene-butadiene-acrylonitrile copolymer (ABS) as a resin additive. By using these resins as resin additives, foams with lower density can be obtained.

The foam of the second embodiment may be formed only of cellulose fibers, polypropylene and a resin additive, and may contain other components as needed.
Examples of other components include flame retardants, fiber-based reinforcements, and foam assistants.
The content of the other components can be, for example, in the range of 0.1% by mass or more and 30% by mass or less as the content relative to the total amount of the foam.

In the foam of the second embodiment, the content of cellulose fiber is 10% by mass to 65% by mass, the content of the resin additive is 0.1% by mass to 30% by mass, and the content of polypropylene Is 5% by mass or more.

The content of the cellulose fiber is 10% by mass or more and 65% by mass or less, and preferably 30% by mass or more and 60% by mass or less. A foam with a low density is obtained as content of a cellulose fiber is 10 mass% or more. Moreover, content of a resin additive and a polypropylene can fully be ensured as content of a cellulose fiber is 65 mass% or less, and the strength of a foam does not run short.

The content of the resin additive is 0.1% by mass or more and 30% by mass or less, and preferably 1% by mass or more and 4% by mass or less. When the content of the resin additive is 0.1% by mass or more, the improvement effect of the expansion ratio by containing the resin additive is sufficiently obtained. Moreover, content of a cellulose fiber and a polypropylene can fully be ensured as content of a resin additive is 30 mass% or less, and the bad influence by the content of a resin additive being too large does not arise.

The content of polypropylene is 5% by mass or more, and preferably 20% by mass or more. The foam which has sufficient intensity | strength is obtained as content of a polypropylene is 5 mass% or more.
In addition, content of the cellulose fiber in a foam, a resin additive, and a polypropylene can be considered to be the same as the ratio of content of the cellulose fiber used as a material of a foam, a resin additive, and a polypropylene.

The density of the foam of the second embodiment is preferably 70 kg / m ³ or less, more preferably 66 kg / m ³ or less. It is suitable as a heat insulating material that the density of a foam is 70 kg / m < ³ > or less. On the other hand, if the density of the foam is too low, the strength of the foam may be insufficient and the application may be limited. Therefore, the density of the foam is preferably 10 kg / m ³ or more, and more preferably 15 kg / m ³ or more.

<Production method of foam>
Next, the method for producing the foam of the present embodiment will be described.
In the method for producing a foam according to the present embodiment, the cellulose fiber, the resin additive and the polypropylene are kneaded, and the cellulose fiber is 10% by mass to 65% by mass, and the resin additive is 0.1% by mass to 30% by mass Thereafter, a step of forming a first kneaded product containing 5% by mass or more of polypropylene (a first kneaded product forming step), and a step of kneading the first kneaded product and water to form a second kneaded product (second And K) a step of evaporating the water of the second kneaded product to generate a foam (foam generation step).

(First kneaded material formation process)
A continuous kneader and a batch kneader can be used as a kneader which knead | mixes a cellulose fiber, a polypropylene, and a resin additive in a 1st kneaded material production | generation process. Examples of continuous kneaders include single-screw kneaders and twin-screw kneaders. Examples of the batch type kneader include a Banbury mixer and a pressure type kneader.

Since the density of the cellulose fiber, polypropylene, and resin additive to be kneaded in the first kneaded product forming step is largely different, the cellulose fiber, polypropylene, and resin additive are mixed in advance before being charged into the kneading apparatus. Is preferred. By introducing the mixture of cellulose fiber, polypropylene and resin additive into the kneading apparatus, a first kneaded material having a uniform composition in a short time can be obtained.
When manufacturing the thing containing other components as a foam of this embodiment, other components are thrown into a kneading apparatus with a cellulose fiber, a polypropylene, and a resin additive in a 1st kneaded material production | generation process, A first kneaded product containing the components is produced.

(2nd kneaded material formation process)
It is preferable to use a continuous-type kneader as a kneading apparatus which knead | mixes a 1st kneaded material and water in a 2nd kneaded material production | generation process. Kneading conditions such as an example of a continuous kneader, a temperature of a cylinder part and a temperature of a die part, a screw rotation speed, a supply speed of water to the continuous kneader, etc. are the foam manufacturing methods of the first embodiment described above. The same as the case. Moreover, you may perform a 1st kneaded material production | generation process and a 2nd kneaded material production | generation process continuously similarly to the case of the manufacturing method of the foam of the above-mentioned 1st Embodiment. For example, using a continuous kneader as a kneader, polypropylene, cellulose fibers, a resin additive, and other components contained as necessary are added to the continuous kneader to form a first kneaded product, Next, water may be supplied to the continuous kneader, and the first kneaded material and the water may be kneaded to form a second kneaded material.

(Foam generation process)
In the foam generation step, the moisture of the second kneaded material extruded from the die portion of the continuous kneader is evaporated to generate a foam. The evaporation of the water content of the second kneaded material can be performed under the atmosphere. Usually, the water content of the second kneaded material is evaporated while being extruded from the die portion of the continuous kneader, and the foam of the second embodiment is generated. The generated foam may be cut into lengths according to the use application, if necessary.

The foam of the second embodiment described above contains 10% by mass to 65% by mass of cellulose fibers, 0.1% by mass to 30% by mass of a resin additive, and 5% by mass or more of polypropylene. The resin additive is vinyl resin, polystyrene resin, polyester resin, polyamide resin, acrylic resin, polyether resin, polyimide resin, elastomer resin, sulfur-containing resin, phenol resin, epoxy resin It is at least one selected from resins. For this reason, the heat conductivity is low, and when used as a heat insulating material, sufficient heat insulation can be obtained.
Moreover, according to the foam manufacturing method of the present embodiment, the second kneaded product obtained by kneading the first kneaded product containing the cellulose fiber, the polypropylene, and the specific resin additive at a specific content, and water. The evaporation of the water content produces a foam, so that a foam with a large amount of foam is obtained.

Third Embodiment
The foam of the third embodiment comprises the above-mentioned cellulose fiber, the above-mentioned polypropylene and polyurethane. The content of cellulose fiber is in the range of 10% by mass to 65% by mass, the content of polyurethane is in the range of 1% by mass to less than 20% by mass, and the content of polypropylene is in the range of 15% by mass to 89% by mass It is inside. Furthermore, the shape of the foam of this embodiment is a shape or strand shape in which a plurality of granular foam particles are linked in a cord shape.

The foam of the third embodiment is obtained by adding water to a kneaded product containing cellulose fibers, polyurethane and polypropylene in a predetermined amount, and foaming the foam, thereby obtaining a foam having a low density and a high strength. It was completed based on the finding that it becomes possible.

The polyurethane has a function to improve the strength of the foam and to improve the amount of foam of the foam. As polyurethane, urethane resins, such as polyester system urethane, polyether system urethane, and polycarbonate system urethane, can be used.

The polyurethane is preferably water-soluble or one having high affinity to water. Polyurethane having a high affinity to water is dispersed throughout the material of the foam together with the foaming agent water at the time of production of the foam, so that the strength of the foam tends to be uniform. The polyurethane used in the production of the foam is preferably a polyurethane solution or an aqueous dispersion of polyurethane (aqueous polyurethane dispersion). The polyurethane preferably has a decomposition temperature of 190 ° C. or higher. When the decomposition temperature is 190 ° C. or more, the polyurethane is less likely to be decomposed and volatilized during the production of the foam.

If the content of polyurethane is too small, it may be difficult to obtain the above-mentioned effects of polyurethane. On the other hand, when the content of polyurethane is too large, the content of cellulose fiber and polypropylene relatively decreases, and the amount of foaming decreases, and the buffer property against physical impact and the heat insulating property may decrease.
From the above reasons, in the foam of the third embodiment, the polyurethane content is set in the range of 1% by mass or more and less than 20% by mass. The polyurethane content is preferably in the range of 3% by mass to 15% by mass.

In addition, when the density of the foam becomes too high, the amount of pores of the foam becomes relatively small, and there is a possibility that the shock absorbing property against physical impact and the heat insulating property may be lowered. For this reason, the density of the foam of the third embodiment is 80 kg / m ³ or less, and more preferably 70 kg / m ³ or less. On the other hand, if the density of the foam is too low, the strength of the foam may be reduced. Therefore, the density of the foam is preferably 10 kg / m ³ or more, and more preferably 15 kg / m ³ or more.

The foam of the third embodiment may be formed only of cellulose fiber, polypropylene and polyurethane, or may contain other components as needed.
Examples of other components include organic flame retardants, inorganic flame retardants, antioxidants, and foam assistants. The content of the other components can be, for example, in the range of 0.1% by mass or more and 30% by mass or less as the content relative to the total amount of the foam. In addition, when it contains another component, it is preferable that it is 35 mass% or more, and, as for sum total content of the polyurethane and a polypyrrole pyrene with respect to the foam whole quantity, it is more preferable that it is 40 mass% or more.

Next, a method of manufacturing the foam of the third embodiment will be described.
The foam production method of the present embodiment comprises cellulose fibers (for example, waste paper cellulose fibers), polypropylene (for example, pelletized or powdery polypropylene), polyurethane (for example, polyurethane solution or aqueous dispersion of polyurethane). Are kneaded to form a first kneaded material (first kneaded material forming process), and the first kneaded material and water are kneaded to form a second kneaded material (second kneaded material forming process) And evaporating the moisture of the second kneaded material to generate a foam (foam generation step). In the first kneaded product, the content of cellulose fibers is in the range of 10% by mass to 65% by mass, the content of polyurethane is in the range of 1% by mass to less than 20% by mass, the content of polypropylene is 15% by mass or more It is preferable to exist in the range of 89 mass% or less. In addition, when content of the polyurethane of a 1st kneading | mixing thing exists in the range of 1 mass% or more and 10 mass% or less, a bead-shaped foam will become easy to be generated in a foam formation process.

(First kneaded material formation process)
A continuous kneader and a batch kneader can be used as a kneader for kneading cellulose fiber, polyurethane and polypropylene in the first kneaded product forming step. Examples of continuous kneaders include single-screw kneaders and twin-screw kneaders. Examples of the batch type kneader include a Banbury mixer and a pressure type kneader.

Since the cellulose fibers, polypropylene, and polyurethane to be kneaded in the first kneaded product forming step differ greatly in density, it is preferable to mix the cellulose fibers, polyurethane, and polypropylene in advance to prepare a mixture before feeding into the kneading apparatus. By supplying the mixture of the cellulose fiber, the polyurethane and the polypropylene to the kneading apparatus, a first kneaded product having a uniform composition in a short time can be obtained.
When manufacturing the thing containing other components as a foam of this embodiment, other components are thrown into a kneading apparatus with a cellulose fiber, a polyurethane, and a polypropylene in a 1st kneaded material production process, and other components are added A first kneaded material containing the mixture is produced.

(2nd kneaded material formation process)
It is preferable to use a continuous-type kneader as a kneading apparatus which knead | mixes a 1st kneaded material and water in a 2nd kneaded material production | generation process. Kneading conditions such as an example of a continuous kneader, a temperature of a cylinder part and a temperature of a die part, a screw rotation speed, a supply speed of water to the continuous kneader, etc. are the foam manufacturing methods of the first embodiment described above. The same as the case. Moreover, you may perform a 1st kneaded material production | generation process and a 2nd kneaded material production | generation process continuously similarly to the case of the manufacturing method of the foam of the above-mentioned 1st Embodiment. For example, using a continuous kneader as a kneader, polypropylene, cellulose fibers, polyurethane, and other components contained as necessary are added to the continuous kneader to form a first kneaded product, and then, Water may be supplied to the continuous kneader to knead the first kneaded product and water to generate a second kneaded product.

(Foam generation process)
In the foam generation step, the moisture of the second kneaded material extruded from the die portion of the continuous kneader is evaporated to generate a foam. The evaporation of the water content of the second kneaded material can be performed under the atmosphere. Usually, the moisture of the second kneaded material is evaporated while being extruded from the die portion of the continuous kneader, and the foam of the third embodiment is generated. The generated foam is cured by cooling such as natural cooling, and then cut into lengths according to the intended use, and used as a heat insulating material, a shock absorbing material, a packaging material, and the like.

In the foam of the third embodiment configured as described above, the content of the cellulose fiber is in the range of 10% by mass to 65% by mass, and the content of the polyurethane is in the range of 1% by mass to less than 20% by mass. Since the content of polypropylene is in the range of 15% by mass to 89% by mass, it has high strength despite its low density. In addition, since the foam of the third embodiment has a low density of 80 kg / m ³ or less, the shock absorbing property against physical impact and the heat insulating property are improved.

The foam of this embodiment described above contains cellulose fiber and polypropylene, and the content of the cellulose fiber is in the range of 10% by mass to 65% by mass, and the density is as low as 80 kg / m ³ or less. Because of the density, the amount of pores is large. For this reason, sufficient heat insulation can be obtained and it can be advantageously used as a heat insulating material, a shock absorbing material, and a packaging material.
In addition, the shape of the foam according to the present embodiment may be used by cutting and processing into various shapes by forming a plurality of granular foam particles in a shape (stringed bead shape) or a strand shape connected in a string shape. Can.

(polypropylene)
A1 (pellet-like polypropylene): Japan Polypropylene Corporation Waymax (registered trademark) MFX6, MFR (temperature: 230 ° C., load: 2.16 kg): 2.5 g / 10 minutes A2 (pellet-like polypropylene): Japan Polypropylene Made by KK, Novatec (registered trademark), MG03BD, MFR (temperature: 230 ° C., load: 2.16 kg): 30 g / 10 minutes A3 (pellet-like polypropylene): manufactured by Prime Polymer Co., Ltd., Prime Polypro (registered trademark) , J106 G, MFR (melt flow rate, temperature: 230 ° C., load: 2.16 kg) 15 g / 10 min. A4 (Pelleted polypropylene): Waymax (registered trademark) MFX8, MFR (melt flow rate, Melt flow rate, Temperature: 230 ° C, load: 2.16 kg) 1.1 g / 10 min

B1a (powdery polypropylene): A1 (pelletized polypropylene) is ground using a blender (manufactured by Waring, Extreme Mill MX-1200XTS), and sieved (2.0 mm mesh, 0.9 mm wire diameter) It is obtained by classifying and collecting particles under the sieve.
B1b (powdery polypropylene): A1 (pelletized polypropylene) obtained by crushing using a medium-sized cutter mill type crusher.
B2 (powdery polypropylene): A2 (pellet-like polypropylene) is pulverized using a blender (manufactured by Waring, Extreme Mill MX-1200XTS) and sieved (2.0 mm mesh, 0.9 mm wire diameter) It is obtained by classifying and collecting particles under the sieve.
B3 (powdery polypropylene): A3 (pellet-like polypropylene) is ground using a blender (manufactured by Waring, Extreme Mill MX-1200XTS), and sieved (2.0 mm mesh, 0.9 mm wire diameter) It is obtained by classifying and collecting particles under the sieve.
B4a (powdery polypropylene): A4 (pellet-like polypropylene) is pulverized using a blender (manufactured by Waring, Extreme Mill MX-1200XTS) and sieved (2.0 mm mesh, 0.9 mm wire diameter) It is obtained by classifying and collecting particles under the sieve.
B4b (powdery polypropylene): A4 (pellet-like polypropylene) obtained by crushing using a medium-sized cutter mill crusher.

(Cellulose fiber)
C1 (waste paper cellulose fiber particles): obtained by disaggregating used paper using a crusher (Masuko Sangyo Co., Ltd., Mascorroider (stone mill type grinding machine)). Average particle size: 160 μm (average value of the results of measuring the dispersion twice using the above method 1)
C2 (coarsely pulverized waste paper cellulose fiber particles): cellulose fiber (Kanehisa Co., Ltd., trade name: comfibe (without additive)) average particle diameter: 6.3 mm (measured by the above method 2)

C3 (crushed waste paper): obtained by cutting waste paper according to the following method 3. Average particle size: 3 mm to 5 mm
(Method 3)
A waste paper is made into a long sheet of 4 mm in width using a shredder (trade name: PSD-12) (Sanwa Supply Co., Ltd.), and the obtained long sheet is cut in a direction substantially orthogonal to the length direction to form a substantially square . ± 1 mm of the target square (4 mm long and 4 mm wide) was taken as the range of the average particle diameter.

C4 (waste paper cellulose fiber particles): obtained by disaggregating waste paper using a crusher (Masuko Sangyo Co., Ltd., Mascorroider (stone mill type grinding machine)). Average particle size: 81 μm (average value of the results of measuring the dispersion twice using Method 1 above)
C5 (crystalline cellulose particles): Avicel PH101 Cat NO. 14204
C6 (oil palm empty fruit bunch (EFB) cellulose fiber particles): A kraft pulped oil palm empty fruit bunch cellulose (EFB) is disintegrated using a crusher (Masuko Sangyo Co., Ltd., Mascorroider (stone mill type grinding machine)) What I got Average particle size: 123 μm (average value of the results of measuring the dispersion twice using Method 1 above)
C7 (waste paper cellulose fiber particles): obtained by disintegrating waste paper using a crusher (cutting-type small crusher). Average particle size: 79 μm (average value of the results of measuring the dispersion twice using the above method 1)
C8 (waste paper cellulose fiber particles): C7 (waste paper cellulose fiber particles) which has passed through a sieve with a mesh size of 40 μm. Average particle size: 39 μm (average value of the results of measuring the dispersion twice using Method 1 above)

C9 (waste paper cellulose fiber particles): C7 (waste paper cellulose fiber particles) which passed through a 100 μm mesh sieve and remained on a 40 μm mesh sieve. Average particle size: 77 μm (average value of the results of measuring the dispersion twice using the above method 1)
C10 (waste paper cellulose fiber particles): C7 (waste paper cellulose fiber particles) which passed through a 150 μm sieve and remained on a 100 μm sieve. Average particle size: 108 μm (average value of the results of measuring the dispersion twice using the above method 1)
C11 (waste paper cellulose fiber particle): A non-printed waste paper obtained by disentangling using a crusher (cutting type small crusher). Average particle size: 84 μm (average value of the results of measuring the dispersion twice using the above method 1)

(Resin additive)
D1 (ABS resin): Acrylonitrile, butadiene, styrene-copolymer resin (manufactured by Denki Kagaku Kogyo Co., Ltd., DENKA (registered trademark), GR-2000) is crushed using a blender (manufactured by Waring Co., Ltd., Extreme Mill MX-1200XTS), It is obtained by classification using a sieve (2.0 mm mesh, wire diameter 0.9 mm) and collecting particles under the sieve.
D2 (PE): Polyethylene (made by Ube Maruzen Polyethylene Corporation, trade name: UM 8510)

D3 (PC resin): Pellet-like polycarbonate resin (Taipei Idemitsu Co., Ltd., trade name: TAFLON IR 2200) is crushed using a blender (Waring Co., Extreme mill MX-1200XTS) and sieved (mesh size 710 μm, wire diameter Classification using 0.35 mm) and collecting particles under the sieve.
D4 (PMMA resin): Pellet-like polymethyl methacrylate resin (manufactured by Asahi Kasei Corp., trade name: Delpet 60N99140) is pulverized using a blender (manufactured by Waring, Extreme Mill MX-1200XTS), and sieved (sieve 850 μm, Classification using a wire diameter of 0.50 mm) and recovery of particles under the sieve.

D5 (PS resin): A polystyrene resin (SGP10 manufactured by PS Japan Ltd.) is crushed using a blender (manufactured by Waring, Extreme Mill MX-1200XTS), and a sieve (2.0 mm mesh, 0.9 mm wire diameter) It is obtained by classification using and collecting particles under the sieve.
D6 (Ethylene-α-olefin copolymer resin): An ethylene-α-olefin copolymer resin (Evolue (registered trademark) SP1022 manufactured by Prime Polymer Co., Ltd.) is crushed using a blender (manufactured by Waring, Extreme Mill MX-1200XTS), It is obtained by classification using a sieve (mesh size: 1.4 mm, wire diameter: 0.7 mm) and collecting particles under the sieve.

(Polyurethane)
E1 (water-based polyurethane dispersion): manufactured by Ube Industries, Ltd., ETERACOLL (registered trademark) UW-1005E, an aqueous dispersion having a polyurethane concentration of 30% by mass.

(Others)
F1: Phosphate ester flame retardant (made by Daihachi Chemical Industry Co., Ltd., SR2550)
F2: obtained by disintegrating boric acid (manufactured by Sigma Aldrich, 03-2900-5-500G-J) using a crusher (manufactured by Masuko Sangyo Co., Ltd., Mascorroider (stone mill type grinding machine)). Average particle size: 128 μm (average particle size was measured using the following method)
F3: Obtained by disaggregating sodium tetraborate (manufactured by Sigma Aldrich, 28-2010-5-500G-J) using a grinder (manufactured by Masuko Sangyo Co., Ltd., Mascorroider (stone mill type grinding machine)) thing. Average particle size: 412 μm (average particle size was measured using the following method)

(Method of measuring average particle size of boric acid and sodium tetraborate)
Since boric acid and sodium tetraborate may be dissolved in ion exchange water, the particle size measurement is performed under the dry measurement conditions shown below using the following measuring apparatus. The particle size measurement is performed twice to calculate an average value, which is taken as the average particle size of the sample.

Measuring device: Laser diffraction / scattering type particle size distribution measuring device (manufactured by HORIBA, Ltd., trade name: LA-950V2)
Measurement condition; Measurement unit: Dry Measurement mode: One shot mode Compressed air: 0.3MPa
Particle size standard: Volume standard Refractive index: 1.50-0.00i (sample refractive index)

Example I-1
105 g of A1 (pellet-like polypropylene) and 45 g of C1 (waste paper cellulose fiber particles) were weighed. The weighed A1 and C1 were separated into 30 containers, and A1 and C1 collected for each container were mixed to obtain a raw material mixture. The raw material mixture obtained has an A1 content of 70% by mass and a C1 content of 30% by mass.

The above raw material mixture is charged into a twin-screw kneading extruder (manufactured by Technobel, KZW15-30MG), die temperature Y1: 180 ° C., cylinder temperature X1 / X2 / X3 / X4: 180 ° C./180° C./180° C. / 180 ° C (X1 to X4 are the temperature of each part from the introduction part of the raw material mixture in the cylinder part to the die part), screw rotation speed 90rpm conditions, then extrude from the tip of the die with a diameter of 3 mm The precursor mixture (first mixture) was obtained.

The obtained first kneaded body was cut into an appropriate length. The obtained cut product was ground using a blender (Waring, Extreme Mill MX-1200XTS). The obtained pulverized material was classified using a sieve (2.0 mm mesh diameter, 0.9 mm wire diameter), and the particulate first kneaded material under the sieve was recovered.

The obtained granular first kneaded material was introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW 15-30 MG), and kneaded under the following kneading conditions I-1. At this time, cold water (5 ° C.) is supplied at a rate of 2 mL / min into the cylinder from between X3 part and X4 part of the cylinder, and the first kneaded material and water are kneaded with X4 part of the cylinder to 2 A mixture was produced. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-like foam having a circular cross section.

Example I-2
105 g of B1a (powdery polypropylene) and 45 g of C1 (waste paper cellulose fiber particles) were weighed. The weighed B1a and C1 were separated into 30 containers, and B1a and C1 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B1a content of 70% by mass and a C1 content of 30% by mass.

The obtained raw material mixture was introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW 15-30 MG), and kneaded under the following kneading conditions I-1. At this time, cold water (5 ° C.) is supplied at a rate of 2 mL / min into the cylinder from between X3 part and X4 part of the cylinder to produce a first kneaded product formed between X1 part to X3 part of the cylinder. The mixture was kneaded with water at X4 part of a cylinder to form a second kneaded material. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-like foam having a circular cross section.

Example I-3
101 g of B1a (powdery polypropylene), 4.5 g of B2 (powdery polypropylene), and 45 g of C1 (waste paper cellulose fiber particles) were weighed. The weighed B1a, B2 and C1 were separated into 30 containers, and B1a, B2 and C1 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B1a content of 67% by mass, a B2 content of 3% by mass, and a C1 content of 30% by mass.

The obtained raw material mixture was introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW15-30MG), and was kneaded under the following kneading conditions I-2. At this time, cold water (5 ° C.) is supplied at a rate of 2 mL / min into the cylinder from between X3 part and X4 part of the cylinder to produce a first kneaded product formed between X1 part to X3 part of the cylinder. The mixture was kneaded with water at X4 part of a cylinder to form a second kneaded material. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-like foam having a circular cross section.

Example I-4
A strand-like foam having a circular cross section was obtained in the same manner as in Example I-3 except that C2 (coarsely pulverized waste paper cellulose fiber particles) was used instead of C1 (waste paper cellulose fiber particles).

Example I-5
67.5 g of B1a (powdery polypropylene) and 82.5 g of C1 (waste paper cellulose fiber particles) were weighed. The weighed B1a and C1 were separated into 30 containers, and B1a and C1 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B1a content of 45% by mass and a C1 content of 55% by mass.
The raw material mixture described above was introduced into a twin-screw kneader-extruder (manufactured by Technobel, KZW15-30MG), and in the same manner as in Example I-1, a string-like precursor-kneaded body (first kneaded material) was obtained.

The obtained first kneaded body was cut into an appropriate length. The obtained cut product was ground using a blender (Waring, Extreme Mill MX-1200XTS). From the obtained pulverized material, classification was performed using a sieve (sieve 850 μm, wire diameter 500 μm), and the granular first kneaded material under the sieve was recovered.

The obtained granular first kneaded product was introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW 15-30 MG), and kneaded under the following kneading conditions I-3. At this time, cold water (5 ° C.) is supplied at a rate of 2 mL / min into the cylinder from between X3 part and X4 part of the cylinder, and the first kneaded material and water are kneaded with X4 part of the cylinder to 2 A mixture was produced. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-like foam having a circular cross section.

Example I-6
105 g of B1a (powdery polypropylene) and 45 g of C4 (waste paper cellulose fiber particles) were weighed. The weighed B1a and C4 were separated into 30 containers, and B1a and C4 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B1a content of 70% by mass and a C4 content of 30% by mass.

The obtained raw material mixture was introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW 15-30 MG), and kneaded under the following kneading conditions I-1. At this time, cold water (5 ° C.) is supplied at a rate of 2 mL / min into the cylinder from between X3 part and X4 part of the cylinder to produce the first kneaded material formed between X1 part to X3 part of the cylinder. The mixture was kneaded with water at X4 part of a cylinder to form a second kneaded material. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-like foam having a circular cross section.

Example I-7
140 g of B4a (powdery polypropylene) and 60 g of C1 (waste paper cellulose fiber particles) were weighed. The weighed B4a and C1 were separated into 30 containers, and B4a and C1 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B4a content of 70% by mass and a C1 content of 30% by mass.

The obtained raw material mixture was introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW 15-30 MG), and kneaded under the following kneading conditions I-5. At this time, cold water (5 ° C.) is supplied at a rate of 2 mL / min into the cylinder from between X3 part and X4 part of the cylinder to produce the first kneaded material formed between X1 part to X3 part of the cylinder. The mixture was kneaded with water at X4 part of a cylinder to form a second kneaded material. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-like foam having a circular cross section.

Example I-8
140 g of B1a (powdery polypropylene) and 60 g of C5 (crystalline cellulose particles) were weighed. The weighed B1a and C5 were separated into 30 containers, and B1a and C5 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B1a content of 70% by mass and a C5 content of 30% by mass.

The above raw material mixture is charged into a twin-screw kneading extruder (manufactured by Technobel, KZW15-30MG), and the die temperature Y1: 165 ° C, cylinder temperature X1 / X2 / X3 / X4: 165 ° C / 165 ° C / 165 ° C / 165 ° C / (where X1 to X4 are the temperatures of each part from the introduction part of the raw material mixture in the cylinder part to the die part), and after kneading under the conditions of screw rotation speed 250 rpm, extrude from the die tip of 3 mm in diameter, A string-like precursor kneaded product (first kneaded material) was obtained.

The obtained granular first kneaded product was introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW 15-30 MG), and kneaded under the following kneading conditions I-3. At this time, cold water (5 ° C.) is supplied at a rate of 2 mL / min into the cylinder from between X2 and X3 of the cylinder, and the first kneaded material and water are kneaded with X3 of the cylinder to 2 A mixture was produced. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-like foam having a circular cross section.

Example I-9
140 g of B1a (powdery polypropylene) and 60 g of C6 (waste paper cellulose fiber particles) were weighed. The weighed B1a and C6 were separated into 30 containers, and B1a and C6 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B1a content of 70% by mass and a C6 content of 30% by mass.
A granular first kneaded product was obtained in the same manner as in Example I-8, except that the obtained raw material mixture was used.

The obtained granular first kneaded material was introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW 15-30 MG), and kneaded under the following kneading conditions I-5. At this time, cold water (5 ° C.) is supplied at a rate of 2 mL / min into the cylinder from between X3 part and X4 part of the cylinder, and the first kneaded material and water are kneaded with X4 part of the cylinder to 2 A mixture was produced. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-like foam having a circular cross section.

Example I-10
50 g of B1a (powdery polypropylene) and 50 g of C1 (waste paper cellulose fiber particles) were weighed. The weighed B1a and C1 were separated into 30 containers, and B1a and C1 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B1a content of 50% by mass and a C1 content of 50% by mass.

The above raw material mixture is introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW15-30MG), and the die temperature Y1: 168 ° C, cylinder temperature X1 / X2 / X3 / X4: 170 ° C / 180 ° C / 180 ° C / 170 ° C / (where X1 to X4 are the temperatures of each part from the introduction part of the raw material mixture in the cylinder part to the die part), and after kneading under the condition of screw rotation speed 250 rpm, extrude from the die tip of 3 mm diameter A string-like precursor kneaded product (first kneaded material) was obtained.

The obtained granular first kneaded material was introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW 15-30 MG), and kneaded under the following kneading conditions I-1. At this time, cold water (5 ° C.) is supplied at a rate of 2 mL / min into the cylinder from between X2 and X3 of the cylinder, and the first kneaded material and water are kneaded with X3 of the cylinder to 2 A mixture was produced. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-like foam having a circular cross section.

Example I-11
47 g of B1a (powdery polypropylene), 3 g of B2 (powdery polypropylene), and 50 g of C1 (waste paper cellulose fiber particles) were weighed. The weighed B1a, B2 and C1 were separated into 30 containers, and B1a, B2 and C1 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B1a content of 47% by mass, a B2 content of 3% by mass, and a C1 content of 50% by mass.
A strand-like foam having a circular cross section was obtained in the same manner as in Example I-10, except that the obtained raw material mixture was used.

Example I-12
268 g of B1a (powdery polypropylene), 12 g of B2 (powdery polypropylene), and 120 g of C1 (waste paper cellulose fiber particles) were weighed. The weighed B1a, B2 and C1 were separated into 30 containers, and B1a, B2 and C1 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B1a content of 67% by mass, a B2 content of 3% by mass, and a C1 content of 30% by mass.
A granular first kneaded product was obtained in the same manner as in Example I-10, except that the obtained raw material mixture was used.

The obtained granular first kneaded material is introduced into a twin-screw kneader (KZW 15-30 MG, manufactured by Technobel Co., Ltd.) in which one tip die is changed from a hole of 3 mm in diameter to a hole of 2 mm in diameter. Kneaded. At this time, cold water (5 ° C.) is supplied at a rate of 8 mL / min into the cylinder from between X2 and X3 of the cylinder, and the first kneaded product and water are kneaded with X3 of the cylinder to 2 A mixture was produced. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 2 mm, and the water was evaporated from the second kneaded product to obtain 10 strands of foam having a circular cross section.

Example I-13
47 g of B1 b (powdery polypropylene), 3 g of B2 (powdery polypropylene), and 50 g of C7 (waste paper cellulose fiber particles) were weighed. The weighed B1b, B2 and C7 were separated into 30 containers, and B1b, B2 and C7 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B1b content of 47% by mass, a B2 content of 3% by mass, and a C7 content of 50% by mass.

The above raw material mixture is charged into a twin-screw kneading extruder (manufactured by Technobel, KZW15-30MG), and the die temperature Y1: 168 ° C., cylinder temperature X1 / X2 / X3 / X4: 170 ° C./170° C./170° C. / 170 ° C / (where X1 to X4 are the temperatures of each part from the introduction part of the raw material mixture in the cylinder part to the die part), and after kneading under the condition of screw rotation speed 250 rpm, extrude from the die tip of 3 mm in diameter, A string-like precursor kneaded product (first kneaded material) was obtained.

Example I-14
70.5 g of B4b (powdery polypropylene), 4.5 g of B2 (powdery polypropylene), and 75 g of C7 (waste paper cellulose fiber particles) were weighed. The weighed B4b, B2 and C7 were separated into 30 containers, and B4b, B2 and C7 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B4b content of 47% by mass, a B2 content of 3% by mass, and a C7 content of 50% by mass.

The above raw material mixture is charged into a twin-screw kneading extruder (manufactured by Technobel, KZW15-30MG), and the die temperature Y1: 168 ° C., cylinder temperature X1 / X2 / X3 / X4: 170 ° C./175° C./175° C. / 170 ° C / (where X1 to X4 are the temperatures of each part from the introduction part of the raw material mixture in the cylinder part to the die part), and after kneading under the condition of screw rotation speed 250 rpm, extrude from the die tip of 3 mm diameter A string-like precursor kneaded product (first kneaded material) was obtained.

The obtained granular first kneaded material was introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW 15-30 MG), and kneaded under the following kneading conditions I-6. At this time, cold water (5 ° C.) is supplied at a rate of 2 mL / min into the cylinder from between X2 and X3 of the cylinder, and the first kneaded material and water are kneaded with X3 of the cylinder to 2 A mixture was produced. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-like foam having a circular cross section.

Example I-15
70.5 g of B1 b (powdery polypropylene), 4.5 g of B2 (powdery polypropylene), and 75 g of C11 (waste paper cellulose fiber particles) were weighed. The weighed B1b, B2 and C11 were separated into 30 containers, and B1b, B2 and C11 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B1b content of 47% by mass, a B2 content of 3% by mass, and a C11 content of 50% by mass.
A granular first kneaded product was obtained in the same manner as in Example I-13, except that the obtained raw material mixture was used.

The obtained granular first kneaded product was introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW 15-30 MG), and kneaded under the following kneading conditions I-7. At this time, cold water (5 ° C.) is supplied at a rate of 2 mL / min into the cylinder from between X2 and X3 of the cylinder, and the first kneaded material and water are kneaded with X3 of the cylinder to 2 A mixture was produced. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-like foam having a circular cross section.

Example I-16
70.5 g of B4b (powdery polypropylene), 4.5 g of B2 (powdery polypropylene), and 75 g of C11 (waste paper cellulose fiber particles) were weighed. The weighed B4b, B2 and C11 were separated into 30 containers, and B4b, B2 and C11 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B4b content of 47% by mass, a B2 content of 3% by mass, and a C11 content of 50% by mass.
A granular first kneaded product was obtained in the same manner as in Example I-14, except that the obtained raw material mixture was used.

Example I-17
90 g of B4b (powdery polypropylene), 45 g of C11 (waste paper cellulose fiber particles), and 15 g of F1 (phosphate ester-based flame retardant) were weighed. Weighed B4b, C11, and F1 were divided into 30 containers, and B4b, C11, and F1 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B4b content of 60% by mass, a C11 content of 30% by mass, and an F1 content of 10% by mass.

The obtained raw material mixture was introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW15-30MG), and kneaded under the following kneading conditions I-8. At this time, cold water (5 ° C.) is supplied at a rate of 2 mL / min into the cylinder from between X2 and X3 of the cylinder to produce a first kneaded product formed between X1 and X2 of the cylinder. The mixture was kneaded with water at X3 part of a cylinder to form a second mixture. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-like foam having a circular cross section.

Example I-18
50 g of B4b (powdery polypropylene) and 50 g of C7 (waste paper cellulose fiber particles) were weighed. The weighed B4b and C7 were separated into 30 containers, and B4b and C7 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B4b content of 50% by mass and a C7 content of 50% by mass.
A strand-like foam having a circular cross section was obtained in the same manner as in Example I-10, except that the obtained raw material mixture was used.

Comparative Example I-1
Example I-2 except using C2 (coarse pulverized cellulose fiber particles) instead of C1 (coarsely pulverized waste cellulose fiber particles) and kneading under the following kneading conditions I-5 instead of the kneading conditions I-1 In the same manner as above, a foam was obtained.

Comparative Example I-2
67.5 g of B1a (powdery polypropylene) and 82.5 g of C1 (waste paper cellulose fiber particles) were weighed. The weighed B1a and C1 were separated into 30 containers, and B1a and C1 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B1a content of 45% by mass and a C1 content of 55% by mass.

The obtained raw material mixture was introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW 15-30 MG), and was kneaded under the following kneading conditions I-3. At this time, cold water (5 ° C.) is supplied at a rate of 2 mL / min into the cylinder from between X3 part and X4 part of the cylinder to produce a first kneaded product formed between X1 part to X3 part of the cylinder. The mixture was kneaded with water at X4 part of a cylinder to form a second kneaded material. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a foam.

Comparative Example I-3
In place of the kneading conditions I-3, the foam was prepared in the same manner as in Comparative Example I-2 except that kneading was performed under the following kneading conditions I-4 and cold water (5 ° C.) was supplied at a rate of 1 mL / min. I tried to manufacture, but the screw stopped during kneading, and no foam was obtained.

Comparative Example I-4
A foam was obtained in the same manner as in Comparative Example I-2 except that C2 (coarsely pulverized waste paper cellulose fiber particles) was used instead of C1 (waste paper cellulose fiber particles).

Comparative Example I-5
A foam was obtained in the same manner as in Comparative Example I-3 except that C2 (coarsely pulverized waste paper cellulose fiber particles) was used instead of C1 (waste paper cellulose fiber particles).

Comparative Example I-6
Instead of C2 (coarsely pulverized waste paper cellulose fiber particles), C3 (waste paper crushed material) was used, and instead of the kneading condition I-1, except that kneading was performed under the following kneading condition I-5, Example I-2 and In the same manner, a foam was obtained.

Comparative Example I-7
A foam was obtained in the same manner as in Example I-2 except that B3 (powdery polypropylene) was used instead of B1a (powdery polypropylene).

Comparative Example I-8
45 g of B1a (powdery polypropylene) and 105 g of C1 (waste paper cellulose fiber particles) were weighed. The weighed B1a and C1 were separated into 30 containers, and B1a and C1 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B1a content of 30% by mass and a C1 content of 70% by mass.
A strand-like foam having a circular cross section was obtained in the same manner as in Example I-1 except that the obtained raw material mixture was used.

[Comparative Example I-9]
Using 143 g of B1a (powdery polypropylene) and 7.5 g of C1 (waste paper cellulose fiber particles), a raw material mixture having a B1a content of 95% by mass and a C1 content of 5% by mass was obtained. In the same manner as Comparative Example I-8, a strand-like foam having a circular cross section was obtained.

Comparative Example I-10
10 g of B1a (powdery polypropylene), 40 g of B2 (powdery polypropylene), and 50 g of C1 (waste paper cellulose fiber particles) were weighed. The weighed B1a, B2 and C1 were separated into 30 containers, and B1a, B2 and C1 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B1a content of 10% by mass, a B2 content of 40% by mass, and a C1 content of 50% by mass.
A strand-like foam having a circular cross section was obtained in the same manner as in Example I-10, except that the obtained raw material mixture was used.

(Kneading conditions I-1)
Die part temperature Y1: 168 ° C, cylinder part temperature X1 / X2 / X3 / X4: 170 ° C / 180 ° C / 180 ° C / 170 ° C, screw rotation speed 60rpm
(Kneading conditions I-2)
Die temperature Y1: 168 ° C, cylinder temperature X1 / X2 / X3 / X4: 170 ° C / 180 ° C / 180 ° C / 170 ° C, screw rotation speed 350rpm
(Kneading conditions I-3)
Die temperature Y1: 168 ° C, cylinder temperature X1 / X2 / X3 / X4: 170 ° C / 180 ° C / 180 ° C / 170 ° C, screw rotation speed 90rpm
(Kneading conditions I-4)
Die temperature Y1: 168 ° C, cylinder temperature X1 / X2 / X3 / X4: 170 ° C / 180 ° C / 160 ° C / 140 ° C, screw rotation speed 30rpm
(Kneading conditions I-5)
Die temperature Y1: 168 ° C, cylinder temperature X1 / X2 / X3 / X4: 170 ° C / 180 ° C / 180 ° C / 170 ° C, screw rotation speed 250rpm
(Kneading conditions I-6)
Die temperature Y1: 168 ° C, cylinder temperature X1 / X2 / X3 / X4: 170 ° C / 175 ° C / 175 ° C / 170 ° C, screw rotation speed 60rpm
(Kneading conditions I-7)
Die temperature Y1: 163 ° C, cylinder temperature X1 / X2 / X3 / X4: 170 ° C / 170 ° C / 170 ° C / 166 ° C, screw rotation speed 60rpm
(Kneading conditions I-8)
Die temperature Y1: 168 ° C, cylinder temperature X1 / X2 / X3 / X4: 170 ° C / 170 ° C / 170 ° C / 170 ° C, screw rotation speed 150rpm

[Evaluation]
The density and thermal conductivity of the obtained foam were measured by the following method. The results are shown in Table 1 together with the composition of the raw material mixture.

(Method for measuring foam density)
A strand of foam is cut perpendicular to the extrusion direction using a razor (GEM, 62-0167), and a test sample for measuring the density of a substantially cylindrical 7 to 8 cm long sample is prepared for each foam. Three were prepared for each. The weight and volume of each of the three test samples were measured, and the density ρ (kg / m ³ ) of each test sample was determined by the following equation (1). The average value of the densities of the three test samples obtained was calculated and used as the foam density. The mass M (kg) of the test sample was measured under the atmosphere, and the volume V (m ³ ) of the test sample was measured by the water displacement method.
ρ = M / V (1)
M: Weight of test sample (kg), V: Volume of test sample (m ³ )

(Method of measuring thermal conductivity of foam)
The thermal conductivity of the foam was measured using a rapid thermal conductivity meter (QTM-500, manufactured by Kyoto Denshi Kogyo Co., Ltd.). A needle type probe (PD-N0, manufactured by Kyoto Denshi Kogyo Co., Ltd.) was used as a probe of the rapid thermal conductivity meter.
A strand-like foam is cut perpendicular to the extrusion direction using a razor (GEM, 62-0167), and a substantially cylindrical test sample of 7 to 8 cm in length is prepared for each foam, 3 each. This was made. The test sample was allowed to stand in a constant temperature and humidity environment of a room temperature of 23 ° C. and a relative humidity of 55% for 12 hours. Thereafter, under the constant temperature and humidity environment, the needle type probe was inserted approximately 35 mm from the center of the cut surface of the test sample, and the thermal conductivity was measured. Further, the thermal conductivity of a reference sample made of polystyrene was measured in the same manner as the test sample.

Then, the thermal conductivity λ (W / mK) of the foam was calculated by the following equation (2).
λ = λS− (λR1−λR0) (2)
λS: Measured value of thermal conductivity of test sample (W / mK), λR0: Determined value of thermal conductivity of reference sample (W / mK), λR1: Measured value of thermal conductivity of reference sample (W / mK)
Table 1 shows the average value of the thermal conductivity measured by preparing three test samples.

The foams of Comparative Examples I-2, I-4, and I-5 were not in the form of strands, but short in length. Therefore, measurement samples for measuring the thermal conductivity could not be collected from the foams of Comparative Examples I-2, I-4, and I-5. In addition, it was not possible to insert the needle type probe for a predetermined length (about 35 mm) directly into the foam of Comparative Examples I-2, I-4 and I-5. Therefore, the thermal conductivity of the foams of Comparative Examples I-2, I-4 and I-5 could not be measured. Moreover, although the measurement sample for measuring the density extract | collected from the foam of comparative example I-2, I-4, I-5 was short in length, and the shape was irregular, the measurement of density is possible. The
In addition, the foams of Comparative Examples I-7 and I-10 had a small amount of foam and had a thin and hard state such as dried spaghetti. Therefore, the needle type probe could not be inserted into the foam of Comparative Examples I-7 and I-10, and the thermal conductivity could not be measured.

As shown in Table 1, the foams of Examples I-1 to I-18 have a density of 80 kg / m ³ or less and a thermal conductivity of 40 × 10 ^-3 W / mK or less, which is low. The In particular, the foams of Examples I-1 to I-17 had a density of 70 kg / m ³ or less and a low density.
In contrast, the foams of Comparative Examples I-1, I-2 and I-4 to I-10 had a density of more than 80 kg / m ³ .
In Example I-2 using cellulose fiber particles (C1) as the cellulose fiber, the content of cellulose fiber is the same, and compared with Comparative Example I-6 using waste paper crushed material (C3) as the cellulose fiber , The density was low.

Example II-1
101 g of B1a (powdery polypropylene), 45 g of C1 (waste paper cellulose fiber particles) and 4.5 g of D1 (ABS resin) were weighed. The weighed B1a, C1 and D1 were separated into 30 containers, and B1a, C1 and D1 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B1a content of 67% by mass, a C1 content of 30% by mass, and a D1 content of 3% by mass.

The obtained raw material mixture was introduced into a twin-screw kneader-extruder (manufactured by Technobel, KZW15-30MG), and kneaded under the following kneading conditions II-1. At this time, cold water (5 ° C.) is supplied at a rate of 2 mL / min into the cylinder from between X3 part and X4 part of the cylinder to produce a first kneaded product formed between X1 part to X3 part of the cylinder. The mixture was kneaded with water at X4 part of a cylinder to form a second kneaded material. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-like foam having a circular cross section.

Example II-2
Example II-1 except using C2 (coarse pulverized cellulose fiber particles) instead of C1 (coarsely pulverized cellulose fiber particles) and kneading under the following kneading conditions II-2 instead of the kneading conditions II-1 In the same manner, a strand-like foam having a circular cross section was obtained.

Example II-3
A strand-shaped foam having a circular cross section was obtained in the same manner as in Example II-1 except that D2 (PE) was used instead of D1 (ABS resin).

Example II-4
70.5 g of B4b (powdery polypropylene), 75 g of C7 (waste paper cellulose fiber particles), and 4.5 g of D3 (PC resin) were weighed. The weighed B4b, C7 and D3 were separated into 30 containers, and B4b, C7 and D3 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B4b content of 47% by mass, a C7 content of 50% by mass, and a D3 content of 3% by mass.

The above raw material mixture is introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW15-30MG), and the die temperature Y1: 168 ° C, cylinder temperature X1 / X2 / X3 / X4: 170 ° C / 180 ° C / 180 ° C / 170 ° C / (where X1 to X4 are the temperatures of each part from the introduction part of the raw material mixture in the cylinder part to the die part), and after kneading under the condition of screw rotation speed 250 rpm, extrude from the die tip of 3 mm in diameter, A string-like precursor kneaded product (first kneaded material) was obtained.

The obtained granular first kneaded product was introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW 15-30 MG), and kneaded under the following kneading condition II-3. At this time, cold water (5 ° C.) is supplied at a rate of 2 mL / min into the cylinder from between X2 and X3 of the cylinder, and the first kneaded material and water are kneaded with X3 of the cylinder to 2 A mixture was produced. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-like foam having a circular cross section.

Example II-5
70.5 g of B4b (powdery polypropylene), 75 g of C7 (waste paper cellulose fiber particles), and 4.5 g of D4 (PMMA resin) were weighed. The weighed B4b, C7, and D4 were separated into 30 containers, and B4b, C7, and D4 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B4b content of 47% by mass, a C7 content of 50% by mass, and a D4 content of 3% by mass.

The above raw material mixture is charged into a twin-screw kneading extruder (manufactured by Technobel, KZW15-30MG), and the die temperature Y1: 170 ° C., cylinder temperature X1 / X2 / X3 / X4: 170 ° C./180° C./180° C. / 170 ° C / (where X1 to X4 are the temperatures of each part from the introduction part of the raw material mixture in the cylinder part to the die part), and after kneading under the condition of screw rotation speed 250 rpm, extrude from the die tip of 3 mm in diameter, A string-like precursor kneaded product (first kneaded material) was obtained.

Example II-6
70.5 g of B4b (powdery polypropylene), 75 g of C8 (waste paper cellulose fiber particles), and 4.5 g of D3 (polycarbonate resin) were weighed. The weighed B4b, C8 and D3 were separated into 30 containers, and B4b, C8 and D3 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B4b content of 47% by mass, a C8 content of 50% by mass, and a D3 content of 3% by mass.

The above raw material mixture is introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW15-30MG), and the die temperature Y1: 172 ° C., cylinder temperature X1 / X2 / X3 / X4: 170 ° C./180° C./180° C. / 172 ° C / (where X1 to X4 are the temperatures of each part from the introduction part of the raw material mixture in the cylinder part to the die part), and after kneading under the condition of screw rotation speed 250 rpm, extrude from the die tip of 3 mm in diameter, A string-like precursor kneaded product (first kneaded material) was obtained.

The obtained granular first kneaded product was introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW 15-30 MG), and kneaded under the following kneading conditions II-4. At this time, cold water (5 ° C.) is supplied at a rate of 2 mL / min into the cylinder from between X2 and X3 of the cylinder, and the first kneaded material and water are kneaded with X3 of the cylinder to 2 A mixture was produced. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-like foam having a circular cross section.

[Example II-7]
70.5 g of B4b (powdery polypropylene), 75 g of C9 (waste paper cellulose fiber particles), and 4.5 g of D3 (polycarbonate resin) were weighed. The weighed B4b, C9 and D3 were separated into 30 containers, and B4b, C9 and D3 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B4b content of 47% by mass, a C9 content of 50% by mass, and a D3 content of 3% by mass.
A strand-like foam having a circular cross section was obtained in the same manner as in Example II-6 except that the obtained raw material mixture was used.

[Example II-8]
70.5 g of B4b (powdery polypropylene), 75 g of C10 (waste paper cellulose fiber particles), and 4.5 g of D3 (polycarbonate resin) were weighed. The weighed B4b, C10 and D3 were separated into 30 containers, and B4b, C10 and D3 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B4b content of 47% by mass, a C10 content of 50% by mass, and a D3 content of 3% by mass.
A strand-like foam having a circular cross section was obtained in the same manner as in Example II-6 except that the obtained raw material mixture was used.

[Example II-9]
188 g of B4b (powdery polypropylene), 200 g of C11 (waste paper cellulose fiber particles), and 12 g of D3 (polycarbonate resin) were weighed. The weighed B4b, C11 and D3 were separated into 30 containers, and B4b, C11 and D3 collected for each container were mixed to obtain a raw material mixture. The raw material mixture obtained has a B4b content of 47% by mass, a C11 content of 50% by mass, and a D3 content of 3% by mass.

The above raw material mixture is introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW15-30MG), and the die temperature Y1: 172 ° C., cylinder temperature X1 / X2 / X3 / X4: 170 ° C./180° C./180° C. / 172 ° C / (where X1 to X4 are the temperatures of each part from the introduction part of the raw material mixture in the cylinder part to the die part), after screwing at 250 rpm screw rotation conditions, extrude from the die tip of 2 mm diameter 7 holes A string-like precursor-kneaded body (first kneaded material) was obtained.

The obtained granular first kneaded product was introduced into a twin-screw kneading extruder (KZW15-30MG, manufactured by Technobel Co., Ltd.) equipped with a tip die having a diameter of 2 mm and 7 holes, and was kneaded under the following kneading conditions II-5. At this time, cold water (5 ° C.) is supplied at a rate of 6 mL / min into the cylinder from between X2 and X3 of the cylinder, and the first kneaded material and water are kneaded with X3 of the cylinder to 2 A mixture was produced. The second kneaded product thus produced was extruded from the tip of a die with a diameter of 2 mm, and the water was evaporated from the second kneaded product to obtain seven strands of foam having a circular cross section.

Example II-10
212 g of B4b (powdery polypropylene), 225 g of C6 (waste paper cellulose fiber particles), and 13.5 g of D3 (polycarbonate resin) were weighed. The weighed B4b, C6 and D3 were separated into 30 containers, and B4b, C6 and D3 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B4b content of 47% by mass, a C6 content of 50% by mass, and a D3 content of 3% by mass.

The above raw material mixture is charged into a twin-screw kneading extruder (manufactured by Technobel, KZW15-30MG), and the die temperature Y1: 166 ° C, cylinder temperature X1 / X2 / X3 / X4: 175 ° C / 175 ° C / 175 ° C / 168 ° C / (where X1 to X4 are the temperatures of each part from the introduction part of the raw material mixture in the cylinder part to the die part), after screwing under the conditions of screw rotation speed 250 rpm, extrude from the die tip of 2 mm diameter 7 holes A string-like precursor-kneaded body (first kneaded material) was obtained.

Example II-11
64 g of B1a (powdery polypropylene), 102 g of C1 (waste paper cellulose fiber particles), 6 g of D3 (polycarbonate resin), 14 g of F2 (boric acid), and 14 g of F3 (sodium tetraborate) were weighed. The weighed B1a, C1, D3, F2, and F3 were divided into 30 containers, and B1a, C1, D3, F2, and F3 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B1a content of 32% by mass, a C1 content of 51% by mass, a D3 content of 3% by mass, an F2 content of 7% by mass, and an F3 content of 7% by mass.

A granular first kneaded product was obtained in the same manner as in Example II-6 except that the obtained raw material mixture was used.

The obtained granular first kneaded product was introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW 15-30 MG), and kneaded under the following kneading conditions II-6. At this time, cold water (5 ° C.) is supplied at a rate of 3 mL / min into the cylinder from between X3 part and X4 part of the cylinder, and the first kneaded material and water are kneaded with X4 part of the cylinder to 2 A mixture was produced. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a strand-like foam having a circular cross section.

Example II-12
94.0 g of B4b (powdery polypropylene), 100 g of C7 (waste paper cellulose fiber particles), and 6.0 g of D5 (PS resin) were weighed. The weighed B4b, C7 and D5 were separated into 30 containers, and B4b, C7 and D5 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B4b content of 47% by mass, a C7 content of 50% by mass, and a D5 content of 3% by mass.

The above raw material mixture is introduced into a twin-screw kneading extruder (manufactured by Technobel, KZW15-30MG), and the die temperature Y1: 168 ° C, cylinder temperature X1 / X2 / X3 / X4: 170 ° C / 180 ° C / 180 ° C / 170 ° C / (where X1 to X4 are the temperature of each part from the introduction part of the raw material mixture in the cylinder part to the die part), after kneading under the condition of screw rotation speed 60rpm, extrude from the die tip of 3 mm in diameter, A string-like precursor kneaded product (first kneaded material) was obtained.

The obtained first kneaded body was cut into an appropriate length. The obtained cut product was ground using a blender (Waring, Extreme Mill MX-1200XTS). From the obtained pulverized material, classification was performed using a sieve (1.4 mm mesh, wire diameter 0.7 mm), and the particulate first kneaded material under the sieve was recovered.

Example II-13
94.0 g of B4b (powdery polypropylene), 100 g of C7 (waste paper cellulose fiber particles), and 6.0 g of D6 (ethylene-α-olefin copolymer resin) were weighed. The weighed B4b, C7 and D6 were separated into 30 containers, and B4b, C7 and D6 collected for each container were mixed to obtain a raw material mixture. The obtained raw material mixture has a B4b content of 47% by mass, a C7 content of 50% by mass, and a D6 content of 3% by mass.

(Kneading conditions II-1)
Die temperature Y1: 168 ° C, cylinder temperature X1 / X2 / X3 / X4: 170 ° C / 180 ° C / 180 ° C / 170 ° C, screw rotation speed 250rpm
(Kneading conditions II-2)
Die temperature Y1: 168 ° C, cylinder temperature X1 / X2 / X3 / X4: 170 ° C / 180 ° C / 180 ° C / 170 ° C, screw rotation speed 150rpm
(Kneading conditions II-3)
Die part temperature Y1: 168 ° C, cylinder part temperature X1 / X2 / X3 / X4: 170 ° C / 180 ° C / 180 ° C / 170 ° C, screw rotation speed 60rpm
(Kneading conditions II-4)
Die part temperature Y 1: 172 ° C., cylinder part temperature X1 / X2 / X3 / X4: 170 ° C./180° C./180° C./172° C., screw rotational speed 60 rpm
(Kneading conditions II-5)
Die part temperature Y1: 168 ° C, cylinder part temperature X1 / X2 / X3 / X4: 175 ° C / 175 ° C / 175 ° C / 168 ° C, screw rotation speed 150rpm
(Kneading conditions II-6)
Die temperature Y1: 168 ° C, cylinder temperature X1 / X2 / X3 / X4: 170 ° C / 180 ° C / 180 ° C / 170 ° C, screw rotation speed 90rpm

[Evaluation]
The density and thermal conductivity of the resulting foam were measured by the method described above. The results are shown in Table 2 together with the composition of the raw material mixture.

As shown in Table 2, the foams of Examples II-1 to II-13 containing a resin additive have a density of 70 kg / m ³ or less and a thermal conductivity of 40 × 10 ^-3 W / mK or less Yes, it was low.

Example III-1
103.5 g of B1a (powdery polypropylene), 45 g of C1 (waste paper cellulose fiber), and 5.0 g of E1 (aqueous polyurethane dispersion) (1.5 g as polyurethane) were weighed. The weighed B1a, C1 and E1 were separated into 30 containers, and B1a, C1 and E1 collected for each container were mixed to obtain a raw material mixture. The composition of the obtained raw material mixture is such that the B1a content is 69% by mass, the C1 content is 30% by mass, and the E1 content is 1% by mass.

The obtained raw material mixture is introduced into a twin-screw kneading extruder (KZW 15-30 MG, manufactured by Technobel Co., Ltd.) divided into four areas X1 to X4 from the introduction part of the raw material mixture in the cylinder part to the die part. And kneading under the following kneading conditions III-1. At this time, cold water (5 ° C.) is supplied at a rate of 2 mL / min from X3 to X4 in the cylinder into the cylinder at a rate of 2 mL / min to form a first kneaded material between X1 to X3 in the cylinder, The first kneaded product and water were kneaded with part X4 to form a second kneaded product. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a foam. The obtained foam was a beaded shape in which a plurality of granular foam particles were linked in a string shape.

Example III-2
Same as Example III-1 except that as raw material mixture, 90 g of B1a (powdery polypropylene), 45 g of C1 (waste paper cellulose fiber) and 50 g of E1 (aqueous polyurethane dispersion) (15 g as polyurethane) were weighed. The foam was produced. The obtained foam was a beaded shape in which a plurality of granular foam particles were linked in a string shape. In the composition of the raw material mixture, the B1a content is 60% by mass, the C1 content is 30% by mass, and the E1 content is 10% by mass.

[Example III-3]
Example III- except that as raw material mixture, 82.5 g of B1a (powdery polypropylene), 45 g of C1 (waste paper cellulose fiber) and 75 g of E1 (aqueous polyurethane dispersion) (22.5 g as polyurethane) were weighed. A foam was produced as in 1. The resulting foam was in the form of a strand having a circular cross section. In the composition of the raw material mixture, the B1a content is 55% by mass, the C1 content is 30% by mass, and the E1 content is 15% by mass.

[Example III-4]
85.5 g of B1a (powdery polypropylene), 4.5 g of B2 (powdery polypropylene), 45 g of C1 (waste paper cellulose fiber), and 50 g of E1 (aqueous polyurethane dispersion) (15 g of polyurethane) were weighed. The raw material mixture was obtained by mixing in the same manner as in III-1. The composition of the obtained raw material mixture is such that the content of B1a is 57% by mass, the content of B2 is 3% by weight, the content of C1 is 30% by mass, and the content of E1 is 10% by mass.

The obtained raw material mixture was introduced into a twin-screw kneader-extruder (KZW 15-30 MG, manufactured by Technobel Co., Ltd.), and kneaded under the following kneading conditions III-2. At this time, cold water (5 ° C.) is supplied at a rate of 5 mL / min from between X3 and X4 of the cylinder into the cylinder at a rate of 5 mL / min to form a first kneaded material between X1 and X3 of the cylinder, The first kneaded product and water were kneaded with part X4 to form a second kneaded product. The second kneaded product thus produced was extruded from the tip of a die having a diameter of 3 mm, and water was evaporated from the second kneaded product to obtain a foam. The obtained foam was a beaded shape in which a plurality of granular foam particles were linked in a string shape.

Comparative Example III-1
As a raw material mixture, 75 g of B1a (powdery polypropylene), 45 g of C1 (waste paper cellulose fiber), and 100 g of E1 (aqueous polyurethane dispersion) (30 g as polyurethane) were weighed and mixed similarly to Example III-1 A foam was produced in the same manner as in Example III-1 except that the obtained mixture was used. The obtained foam had an indeterminate shape having a plurality of bulged convex portions. The composition of the raw material mixture is such that the B1a content is 50% by mass, the C1 content is 30% by mass, and the E1 content is 20% by mass.

(Kneading conditions III-1)
Die part temperature Y1: 168 ° C, cylinder part temperature X1 / X2 / X3 / X4: 170 ° C / 180 ° C / 180 ° C / 170 ° C, screw rotation speed 60rpm
(Kneading conditions III-2)
Die temperature Y1: 168 ° C, cylinder temperature X1 / X2 / X3 / X4: 170 ° C / 180 ° C / 180 ° C / 170 ° C, screw rotation speed 350rpm

[Evaluation]
The density and tensile breaking specific energy of the resulting foam were measured. The density of the foam was measured by the method described above. The tensile breaking specific energy of the foam was measured by the following method. The results are shown in Table 3 together with the composition of the raw material mixture. Further, the tensile breaking specific energy was also measured for the foam prepared in Example I-2. The results are shown in Table 3.

(Measurement method of tensile rupture specific energy of foam)
The tensile breaking energy of the foam was measured using a universal tester (EZ-LX, manufactured by Shimadzu Corporation). The test sample in the form of a strand was cylindrically shaped, and the test sample in the form of a bead was prepared by cutting the connection portion of the granular foam particles to a length of 8 cm to prepare three test samples each. The test sample was attached between the jigs of the universal testing machine (a distance between jigs of 5 cm) and subjected to a tensile test to create a stress-strain curve. The tensile breaking energy U (Nm) was determined from the area value under the obtained stress-strain curve using analysis software (Trapezium X Ver 1.4.0) attached to the universal testing machine.
The tensile rupture specific energy Us (Nm / g) was calculated by the following equation (3). In addition, in Table 3, the average value of the tensile breaking specific energy which produced and measured three test samples was described.
Us = U / Mi (3)
Mi: Test sample mass (g) attached between jigs (distance between jigs 5 cm), U: tensile energy to break (Nm)

The foams of Examples III-1 to III-4 containing polyurethane within the scope of the present invention were confirmed to have higher tensile breaking specific energy than the foam of Example I-2 not containing polyurethane. The In addition, the foam of Comparative Example III-1, which contains polyurethane in excess of the scope of the present invention, has a significant reduction in tensile breaking specific energy. This is considered to be due to the fact that the density of the foam became too high by containing a large amount of polyurethane.

The foam of the present invention can be advantageously used as a heat insulating material, a shock absorbing material, and a packaging material.

Claims

Contains cellulose fiber and polypropylene,
The content of the cellulose fiber is in the range of 10% by mass to 65% by mass,
A foam characterized by having a density of 80 kg / m 3 or less.
The foam according to claim 1, wherein the plurality of granular foam particles are in the form of strands or in the form of strands.
It consists of the cellulose fiber and the polypropylene,
The foam according to claim 1, which has a density of 70 kg / m 3 or less.
Furthermore, it contains a resin additive,
The resin additive includes vinyl resin, polystyrene resin, polyester resin, polyamide resin, acrylic resin, polyether resin, polyimide resin, elastomer resin, sulfur-containing resin, phenol resin and epoxy resin. At least one selected from the group consisting of resins,
The content of the resin additive is 0.1% by mass or more and 30% by mass or less,
The foam according to claim 1, wherein the content of the polypropylene is 5% by mass or more.
The foam according to claim 4, which has a density of 70 kg / m 3 or less.
Furthermore, it contains polyurethane,
The content of the polyurethane is in the range of 1% by mass to less than 20% by mass,
The foam according to claim 1, wherein the content of the polypropylene is in the range of 15% by mass to 89% by mass.